GbetaL, a positive regulator of the rapamycin-sensitive pathway required for the nutrient-sensitive interaction between raptor and mTOR

Kim DH, Sarbassov DD, Ali SM, Latek RR, Guntur KVP, Erdjument-Bromage H, Tempst P, Sabatini DM · 2003 · Molecular Cell · Atlas ID KIM2003

What this study shows

Discovered mLST8 (GbetaL), the third core subunit that clamps onto mTOR's kinase domain and stabilizes the complex. It fine-tunes how tightly Raptor holds mTOR in response to nutrients - a small but essential cog that later turned out to be especially critical for the mTORC2 complex.

Abstract

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mTOR and raptor are components of a signaling pathway that regulates mammalian cell growth in response to nutrients and growth factors. Here, we identify a member of this pathway, a protein named GbetaL that binds to the kinase domain of mTOR and stabilizes the interaction of raptor with mTOR. Like mTOR and raptor, GbetaL participates in nutrient- and growth factor-mediated signaling to S6K1, a downstream effector of mTOR, and in the control of cell size.

Read the full abstract on PubMed →

At a glance

Evidence type	M Molecular — cells, biochemistry, structure Marked M because it is molecular or in-vitro work (model: Human cells (biochemistry)) rather than a whole-organism health-outcome study. That is often exactly where causal biology gets established -- the code says which system the finding was shown in, and nothing about how good the work is.
Study type	5 - Mechanistic / In Vitro
Model system	Human cells (biochemistry)
Journal	Molecular Cell
Year	2003
Peer reviewed	Yes
Record last updated	2026-07-29
Source	DOI 10.1016/s1097-2765(03)00114-x · PMID 12718876

Extracted findings

These fields were extracted from the paper with AI assistance and have not been checked against the source. Read them as a pointer into the paper, not as curated claims; where they disagree with the curated summary above, the curated summary stands.

Intervention	Biochemical – identification of GβL (mLST8)
Target	mTOR / raptor / GβL (mLST8)
Model	Human cells (biochemistry)
Effect	GβL binds the mTOR kinase domain and stabilizes the raptor–mTOR interaction; stimulates nutrient-sensitive signaling to S6K1 and cell-size control

In the Atlas

Links in the pathway map

Supports mLST8 required-for mTORC2

Cite this paper

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Kim, D. H., Sarbassov, D. D., Ali, S. M., Latek, R. R., Guntur, K. V. P., Erdjument-Bromage, H., Tempst, P., & Sabatini, D. M. (2003). GbetaL, a positive regulator of the rapamycin-sensitive pathway required for the nutrient-sensitive interaction between raptor and mTOR. Molecular Cell. https://doi.org/10.1016/s1097-2765(03)00114-x

@article{KIM2003,
  author       = {Kim, D. H. and Sarbassov, D. D. and Ali, S. M. and Latek, R. R. and Guntur, K. V. P. and Erdjument-Bromage, H. and Tempst, P. and Sabatini, D. M.},
  title        = {{GbetaL, a positive regulator of the rapamycin-sensitive pathway required for the nutrient-sensitive interaction between raptor and mTOR}},
  journal      = {Molecular Cell},
  year         = {2003},
  doi          = {10.1016/s1097-2765(03)00114-x},
  note         = {PMID: 12718876},
}

Cite this Atlas record

The record is the Atlas's own work — the evidence label, the extracted findings and the links. It is cited as part of the dataset, not as the paper.

Barton, O. (2026). Oliver's mTOR Atlas (record KIM2003) [Data set]. https://mtor-atlas.org/study/KIM2003/ · Dataset DOI 10.5281/zenodo.22059963

@misc{atlas_KIM2003,
  author       = {Barton, Oliver},
  title        = {{Oliver's mTOR Atlas}, record KIM2003},
  howpublished = {Data set},
  year         = {2026},
  url          = {https://mtor-atlas.org/study/KIM2003/},
  doi          = {10.5281/zenodo.22059963}
}

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